GR7 Science Practice Items

Which of these describes a material that is best to use for a hip replacement?

• a soft material that bends with the movement of the body

• a mesh material that allows fluid in the body to pass through it

• a hard metal material that supports the weight of the body

• a solid dissolvable material that disappears after the body heals

Answer explanation

A hard metal material is ideal for hip replacements as it provides the necessary strength and support to bear body weight, ensuring durability and stability during movement.

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

NGSS.MS-ETS1-3

NGSS.MS-ETS1-4

The graph shows atmospheric CO2 levels over time. Which activity most likely contributed to the changes in atmospheric CO2 levels after the year 1800?

• transforming vacant lots into parks and recreational areas

• growing seasonal produce in community gardens

• driving electric vehicles with low emissions

• producing goods in large factories

Answer explanation

After 1800, industrialization led to increased production in large factories, which burned fossil fuels and released significant CO2 into the atmosphere, contributing to rising CO2 levels. Other options do not have the same impact.

Tags

NGSS.MS-ESS3-4

A sample of pure cesium (Cs) reacts with water. Under standard conditions, which of these elements react in a similar way to water as cesium (Cs)?

• silicon (Si)

• neon (Ne)

• potassium (K)

• iridium (Ir)

Answer explanation

Potassium (K) is an alkali metal like cesium (Cs) and reacts vigorously with water, producing hydrogen gas and hydroxides. Silicon (Si), neon (Ne), and iridium (Ir) do not react with water in a similar manner.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which type of gold is a pure substance?

• Rose Gold

• White Gold

• 18K Gold

• 24K Gold

Answer explanation

24K Gold is considered pure gold, containing 99.9% gold content. In contrast, Rose Gold, White Gold, and 18K Gold are alloys mixed with other metals, making them less than 100% pure.

If CO2 lowers the pH of water, which statement best explains the processes that occurred in the beaker?

• The aquatic plant released CO2 that the snail used to make sugars.

• The water pH lowered as CO2 was consumed by the aquatic plant.

• The snail breathed in CO2 from the water.

• The snail released CO2 into the water.

Answer explanation

The correct choice explains that as the aquatic plant consumes CO2 during photosynthesis, it lowers the water's pH. Additionally, the snail releases CO2 into the water, contributing to the overall CO2 levels.

Tags

NGSS.MS-LS2-3

NGSS.MS-LS2-4

The model shows a pure substance in a glass jar undergoing a change of state. Based on the model, the changes observed are most likely caused by: M. a decrease in the total mass of the substance under the glass jar without a change in temperature or pressure. P. an increase in the temperature of the substance without a change in pressure. R. a decrease in the temperature of the substance without a change in pressure. S. an increase in the atmospheric pressure outside the glass jar without a change in temperature.

• a decrease in the total mass of the substance under the glass jar without a change in temperature or pressure

• an increase in the temperature of the substance without a change in pressure

• a decrease in the temperature of the substance without a change in pressure

• an increase in the atmospheric pressure outside the glass jar without a change in temperature

Answer explanation

The model indicates a change of state, which is typically due to temperature changes. An increase in temperature without a change in pressure allows the substance to transition to a different state, making this the correct choice.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which table best describes both mitosis and meiosis?

• Process | Description of Process | Comparison of Daughter Cells to Parent Cells Mitosis | One cell becomes four cells. | Genetically identical Meiosis | One cell becomes two cells. | Genetically different

• Process | Description of Process | Comparison of Daughter Cells to Parent Cells Mitosis | One cell becomes four cells. | Genetically different Meiosis | One cell becomes two cells. | Genetically different

• Process | Description of Process | Comparison of Daughter Cells to Parent Cells Mitosis | One cell becomes two cells. | Genetically identical Meiosis | One cell becomes four cells. | Genetically different

• Process | Description of Process | Comparison of Daughter Cells to Parent Cells Mitosis | One cell becomes two cells. | Genetically identical Meiosis | One cell becomes four cells. | Genetically identical

Answer explanation

The correct table shows that mitosis results in two genetically identical daughter cells, while meiosis produces four genetically different cells. The other options incorrectly describe the processes.

Tags

NGSS.MS-LS3-2

The graph shows the boiling points of three elements in Group 17 of the periodic table. Which point on the graph best predicts the boiling point of chlorine, Cl₂?

• point W

• point X

• point Y

• point Z

Answer explanation

Point X best predicts the boiling point of chlorine, Cl₂, as it aligns with the trend of increasing boiling points in Group 17 elements, where chlorine is positioned between fluorine and bromine.

Which statement identifies the mixture and provides evidence that best supports the claim?

• Substance 1 is a mixture because the crystals turn black when heated.

• Substance 2 is a mixture because the crystals turn different colors when heated.

• Substance 3 is a mixture because the liquid bubbles and then evaporates when heated.

• Substance 4 is a mixture because the liquid evaporates and leaves small blue crystals behind.

Answer explanation

Substance 2 is identified as a mixture because the crystals changing colors when heated indicates the presence of different components, which is characteristic of mixtures.

Tags

NGSS.MS-PS1-2

What was the procedure used by students to study the effects of temperature on water and air?

• Students used a thermometer to measure temperature changes.

• Students observed the color change in water and air.

• Students recorded the time taken for water to boil.

• Students measured the volume of air and water.

Answer explanation

Students used a thermometer to measure temperature changes, which is essential for studying the effects of temperature on water and air. This method provides accurate data on how temperature influences these substances.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4